The invention relates to contact lenses having a sparkle effect and sparkle additives useful in the production of cosmetic contact lenses. In particular, the invention is directed to sparkle additives that use interference particles to provide a sparkle effect to the lenses.
The use of cosmetic contact lenses to alter or augment the natural color of the iris is well known. Colorants used in cosmetic lenses generally are prepared with binding polymer to form a colorant mix. A variety of pigments are commercially available for use in the production of tinted contact lens. Typically, the cosmetic lenses use either or both opaque and translucent colors to change the color of an iris, as for example, from brown to blue. Additionally, cosmetic lenses have been manufactured that attempt to enhance the eye to produce a more striking appearance so as to draw attention to the eye with or without changing the color of the iris. For example, colorants that incorporate pigments capable of producing a pearl-type luster, phosphorescent pigments to produce a glow-effect, pigments with reflective material and the like are known.
These lenses are disadvantageous because either the enhancement is too subtle to be noticed when the lens is on-eye or the enhancement lends an unnatural appearance to the wearer's iris. Cosmetic lenses that enhance the appearance of the eye without seeming unnatural are desirable.